1. Field of the Invention
The present invention relates to an apparatus for the feed and control of the speed of a hydraulic motor having variable swept volume, which enables variations in the resisting torque applied to the motor to be met, while the rotational speed is kept constant or is varied in accordance with the desired excursion.
2. Description of the Prior Art
For certain uses of hydraulic motors and, in particular, in the case where such motors are used on injection molding machines for plastics materials, for driving the screw for loading the granular material to be molded, the problem arises of keeping the rotational speed of the motor constant, or of varying it according to a predetermined function, independently of variations in the resisting torque applied which can result from differing behaviors in the devices driven by the motor.
Such control or regulation, moreover, must be carried out in a manner which reduces to a minimum the loss of energy, that is to say without the need to dump the feed when the latter is in excess, but appropriately controlling the behavior of the motor under all conditions.